Well pump dynagraph



Oct. 26, 1937. w. E.- GILBERT Er AL NELL PUMP DYNAGRAPH Filed Mar'oh 1e, 1936 2 sheets-sheet 1 Odi. 26, 1937. w EI GILBERT E -r AL 2,097,150

WELL PUMP DYNAGRAPH Filed March 16, 1936 2 Sheets-Sheet 2 'Patented Oct. 26, 1937 UNITED STATES PATENT oFFiea WELL PUMP DYNAGRAPH Walton E. Gilbert, Pasadena, and Sumner E. Sargent, Huntington Park, Calif., assignois to Shell Development Company, San Francisco, Calif., a corporation of Delaware, and Sargent Engineering Company, Los Angeles, Calif., a corporation of California, jointly Application March 16, 1936, Serial No. @8.999%

8 Claims. (Cl. 265-2) This invention pertains to reciprocating well pumps and is more particularly concernedvwith apparatus for recording the stroke and lifting force, and therefore the power, of such pumps y on indicator diagrams traced within the well.

The usual practice in petroleum production has been up to the present to determine the stroke of an oil well pump and the forces acting at the pump from data obtained at the well head. These determinations, however", were often inaccurate,

considerable errors being introduced by such factors as friction and/or the stretching of various mechanical parts connecting the pump at the F bottom of the well with the recording apparatus at the well head.

It is therefore an object of this invention to provide a recorder device of a simple and rugged construction, which may be connected directly to the pump and lowered therewith into the well for recording on a chart the actual stroke of the pump and lthe forces acting at the pump as functions of the reciprocating motion of the pull rod actuating the plunger of the pump and of the elastic changes in length of said pull rod due to the alternating stresses to which it is subjected during pumping.

It is another object of this invention to provide `a device recording the elastic changes in the length of a portion of the pull 10d so located' in the well that said elastic changes are due substantially only to the pnping forces exerted, any elastic changes due to the Weight of the pull or sucker rods located below said portion being negligible as compared therewith.

It is a further object of this invention to pro-1 vide aA mechanical system of operation whereby the power developedv by a pump may be continu- .ously recorded on a chart at the pump for a plurality ofoperating cycles by means of a chartfeeding mechanism.

These and other objects and useful features of the invention will be understood from the following description taken with reference to the attached drawings, wherein:

Fig. 1 is a vertical view, partly in cross-section, diagrammatically showing one form of the present recording device, V

Fig. 2 is a cross-section taken along the line 2-2 of Fig. 1,

Fig. 3 is a detailed view showing the type of indicator diagrams traced by means of the recorder,

Fig. 4 is a perspective view of the chart-feeding mechanism located at the well head. y

Referring tc Fig. 1, a tubing string 'I holds a to the well head.

pump 21, provided with a check valve 29. A4 plunger 34 moves within the cylinder of the pump and is provided with a check valve 36. On the upward stroke of the plunger, the pump cylinder is filled by suction with the well liquid, valve 2d being open and valve closed. 0n the down-` ward stroke of the plunger, valve 2S is pressed against its' seat, while valve opens and admits the liquid inside the plunger 3d, whence it is Although in the preferred embodiment of Fig.

1, the recorder is shown directly above the pump, it is possible to mount the recorder at some distance above the pump. This distance should not, however, be too great in order that the elastic changes in the length ci the pull rod, recorded in the manner described below, be not affected by the weight of the portion of the pull rod between the recorder and the pump. A pull rod 26, actuating 'the plunger and also forming a working part oi the recorder, entends through cover tube 21S and is connected at its upper end to the string of sucker rods 2 by means of coupling t. The sucker rods 2 extend to the well head and are there actuated by a motor or other suitable reciprocating means.

On the threaded portion 5 oi the upper end ci the pull rod 26 is mounted a ball bearing mechanism t, held by a housing sleeve iii, which is free to rotate around the pull rod 2S. The hous ing sleeve It is closed at the top by a bushing- 3, and has at its lower end threads 7, holding a Vrevolving tube ii, with two helical slots 9 cut in its outer surface. The revolving tube il nts inside the recorders cover tube 2B, which, as stated above, is supported at its lower end by the pump' barrel. Lugs i 2 are permanently set in the upper part of cover tube 26 and are adapted to slide along the helical slots 9 of revolving tube il, so that any axial motion of the revolving tube li with regard to the cover tube 24 causes the tube Il torotate on the bearings 8 by means of which it is attached to the pull rod 26. It will be seen that the'direction of the rotational motion of revolving tube H will reverse when the direction of the axial motion of pull rod 26 is reversed. The lower end of revolving tube II carries an adapter tube I3 provided with a marker, such for.

deformable material such, for example, as one or several wrappings of a copper. sheeting of 0.01 inch thickness. Cylinders made in this manner have the advantage of not being impaired or destroyed by contact .with iluids, andv may moreover be easily withdrawn from the recorder and attened out to facilitate the analysis of the record obtained.

The recording cylinder 22 is supported by a winged nut I1 carried on the threaded lower end of pull rod 26. The winged nut and the recording cylinder are kept from rotating with regard to the cover tube 24 by the action of lugs I9 sliding in two opposite vertical slots I6 cut on the inner side of cover tube 24. Sometimes, it may be desirable to cut holes 2l near the 4bottom of the cover tube 24 to provide for an easy inilow and outow of oil and thus prevent the instrument to absorb energy by acting as a dashpot. The recording cylinder 22 slidably extends through a bushing I5 carried by the adapter tube I3, the purpose of this bushing being to center the revolving tube II and the recording cylinder 22 with regard to each other.

It is clear from the above description of the cooperating parts of the present device cthat with every stroke of the plunger 34, actuated by the pull rod 26, both the recording cylinder 22 and the marker 29 move together axially since they are both attached to said pull rod 26. The action of the lugs I9 sliding in vertical slots I6 prevents any rotational motion of the recording cylinder 22 with regard to the cover tube 24, while the action of the lugs I2 axed onto tube 24 and sliding in the helical slots 9 causes the revolving tube II together with the adapter tube I3 and the marker 20 to rotate with regard to the cover tube 24 and the cylinder 22, the point of the marker 20 tracing on the cylinder 22 horizontal lines 4I and i12 (shown in Fig. 3) of a length proportional to the travel of the lugs I2 in the helical slots 9 or, in other words, to the stroke of the pull rod 26 and of the plunger 34.

The pull rod 26 is subjected during pumping to various stresses, such as the tension stress on the upward stroke, which causes changes in its length on each reversal in the direction of its axial motion. The changes in length of the pull rod 26 between the points I? and 5 where the recording cylinder 22'and the marker 20 are respectively attached thereto cause the recording cylinder and the marker to be displaced axially with regard to each other. As shown in Fig. 3, this displacement is recorded as the distance between the horizontal line 4I, traced by the marker on the recording cylinder during the upward stroke ofthe plunger, and the horizontal line 42 traced during the downward stroke of the plunger. Since the stresses to which the pull rod is subjected are within the elasticity limits of the material of which it is made, the vertical distance between lines 4I and 42 is proportional to the force acting on the plunger. of the lines 4I and 42, as explained above, is proportional to the stroke of the plunger, the area of the gure traced by marker 20 is proportional to the work done at the pump during one Since the length cycle of its operation. By calibrating the recorder in suitable units, the power developed by the pump may therefore be conveniently measured on the diagram obtained.

To obtain a displacement of the successive records 'of individual cycles during a certain -period of operation or the pump, the sucker rods 2 may be rotated at the surface, for example, after each cycle, or after any desired number of cycles. The rotation of the sucker rods 2 1s transmitted to the pull rod 26, and causes the winged nut I 1, which is prevented from rotating by the lugs I6, to travel upwards on the screw threads of pull rod 3, the recording cylinder 22 being thereby raised by a certain amount with regard to the stylus 20 for each successive cycle. The type of diagram obtained in this manner is shown at 41, Fig. 3.

The sucker rods 2 may be rotated either manually or automatically, for example, by means of a device such as the- Sargent rotor, shown in Fig. 4.

This rotor, which forms no part-of this invention, is mounted at 5I on the end of the top length 2 of the sucker rod string, attached to the Walking beam 5I! by means of a rod beam hanger 52. The rotor 5I is provided with a lever 53, connected with the walking beam by a chain 55. Due tothe angular displacement of the rod beam hanger 52 with regard to the walking beam 5U during pumping, the chain 55 is stretched on each downward stroke and pulls up the lever 53, which in turn operates to rotate the sucker rods 54 by means of the rotor mechanism 5I.

For example, during one run of the present recording device, the rotor moved the sucker rods through one-fteenth of a turn during each downward stroke, and since the winged nut I1 had sixteen threads to the inch, the axial movement' of the recording cylinder 22 with regard to the marker 20 was about 0.0042 inch per cycle, such displacement being discernible on the record obtained.

It is understood that other means of rotating the rods may be used; For example, it has been found that one set of readings may be set apart from the others by stopping the pump and rotating the rods manually, the stylus tracing a line 45 during this operation, as shown in Fig. 3.

It is understood that neither the above description nor the drawings illustrating a preferred embodiment of the present device should in any waybe taken to limit this invention which is capable of many modifications falling within the scope of the appended claims.

Thus, for example, the recording cylinder may be rotatably mounted on a bearing, while the marker may be provided with means preventing it from rotation, an indicator diagram similar to the one described above being obtained in this case.

It is also possible to record the stroke of a pump directly by the axial movement of the marker, while causing the changes in length of the pull rod to rotate the chart and the marker with regard to each other by amounts proportional to the forces applied to the pull rod.

Likewise, the chart feeding mechanism need elastic link, comprising, for example, a strong and suitably calibrated spring may be inserted in the pull rod between the points of attachment of the chart and the marker to increase the amount of their relative axial displacement with regard to each other during each operating cycle.

We claim as our invention:

1. Ina device for recording the power of a reciprocating well pump comprising a pull rod located in the well, and a motor reciprocating said pull rod in the well and causing elastic changes in its length, a chart and a marker supported by said pull rod, means for displacing the chart and the marker with regard to each other by an amount proportional to the stroke of the pump, means for displacing the chart and the marker with regard to each other transversely to said last displacement by an amount proportional to the elastic change in length of the pull rod, and means to record said displacements on the chart by the marker.

2. In a device for recording the powerl of a reciprocating well pump comprising a pull rod located in the well, and a motor reciprocating said' pull rod in the well and causing elastic changes in its length, a chart and a marker in contact with each other and attached at spaced points to said pull rod, means for displacing the chart and the marker with regard to each other by an amount proportional to the stroke of the pump, means to displace the chart and the marker with regard to each other transversely to said last displacement by an amount proportional to the change in length of the pull rod between the points of attachment for the chart and of the marker, and means to record said displacements on the chart by the marker.

3. In a device for recording the power of a reciprocating well pump comprising a pull rod located in the well and a motor reciprocating said pull rod in the well and causing elastic changes in its length, a cylindrical chart and a v marker in contact with each other and attached at spaced points to said pull rod, means for rotating the chart andthe marker with regard to each other by an amount proportional to the stroke of the pump, means for displacing axially the chart and the marker with regard to each other by an amount proportional to the change in length of the pull rod between the points of attachment of the chart and of the marker, and means for recording said rotationaland axial displacements on the chart by the marker.

4. In a device for recording the power of a reciprocating well pump comprising a pull rod, and a motor reciprocating said pull rod in the well and causing elastic changes in its length, a cylindrical chart attached to the pull rod, means to prevent the rotation of said chart around the pull rod, a marker rotatably attached to the pull rod at a point spaced from the point of attachment of the chart, said chart and marker being in contact with each other, means for rotating the y marker withregard to the chart by an amount proportional to the stroke of the pump, means for axially displacing the chart and the marker with regard t each other by an amount proportional to the change in length of the pull rod between the points of attachment of the chart and the marker, and means for recording said rotational and axial displacements on` the chart by the marker.

5. In a device for recording the power of a reciprocating pump located in a well and actuated by a pull rod, a cover tube rigidly mounted on the body of the pump around the lower end of said pull rod, a cylindrical chart supported by the lower end of said pull rod within said tube, means to prevent the rotation of the chart with regard to the cover tube, a cylinder rotatably attached to the pull rod and movably fitting inside the cover tube, helical slots on the outside surface of said cylinder, a marker mounted on said cylinder, said marker being in contact with said chart, lugs inwardly mounted on the cover tube and adapted to slide in said helical slots, and means comprising said lugs and said slots to rotate said cylinder with regard to the cover tube by the motion of the pull rod.

6. In a device for recording over a plurality of operating cycles the power of a reciprocating well pump comprising a pull rod located in the wel! and a motor reciprocating said pull rod in the well and causing elastic changes in its length, a chart and a marker supported by said pull rod, means for displacing during each pumping cycle the chart and the marker with regard to each other by an amount proportional to the stroke or' the pumps and for returning them to their original position, means for displacing during each cycle the chart and the marker with regard to each other transversely to the rst named displacement by an amount proportional to the elastic change in length of the pull rod, and for returning them to their original position, feeding means for continuously displacing the chart and the marker with regard to each other in an axial direction, and means for recording said displacements on the chart by the marker.

7. In a device for continuously recording the power of a reciprocating pump located in a well and actuated by a pull rod, a cover tube rigidly mounted on the body of the pump around the lower end of said pull rod, said lower end being provided with threads, a cylindrical chart supported on said threads within said tube, means to prevent the rotation of the chart with regard to the cover tube, a cylinder rotatably attached to the pull rod and movably iitting inside said cover tube, helical slots on the outside surface of said cylinder, a marker mounted on said cylinder, said marker being in contact with said chart, lugs inwardly mounted on the cover tube and adapted to slide in said helical slots, means'comprising said lugs and said slots to rotate said cylinder with regard to said cover tube by the motion of the pull rod, and means to move the chart axially on the threaded part of the pull rod by rotating said tent of said relative axial motion, means to translate the axial motion of the pull-rod intoa transverse motion of the chart with regard to the marker, and to record the extent of said relative transverse motion.

WALTON E. GILBERT. SUMNER B. SARGENT. 

